Lens centering and beveling machine



July 14, 1964 w SQQNG ETAL 3,140,567

LENS CENTERING AND BEVELING MACHINE Filed Jan. 16, 1963 4 Sheets-Sheet l l INVENTORS= WILLIAM E. SOONG ROBERT E. MILLER JAMES DES JARDINS L AWRENCE "SHAR PER BY JJWM, 624% J- P ATTORNEY- y 1964 w. E. sooNcs, 'UETAL 3,140,567

LENS CENTERING AND BEVELING MACHINE Filed Jan. 16, 1963 4 Sheets-Sheet 2 Amplifier s2 I8 E4 68 67 64 A [Q INVENTORS= 664;] 72 WILLIAM E. SOONG ROBERT E. MILLER JAMES 05s JARDlNS LAWRENCEHsHARSER J .pm 0- M A TTORN EYS.

y 14, 1964 w. E. SOONG ETAL 3, 0,567

LENS CENTERING AND BEVELING MACHINE Filed Jan. 16, 1963 4 Sheets-Sheet 3 INVENTORS= WILLIAM E. SOONG ROBERT E. MILLER JAMES DES JARDINS LAWRENCEHSHARPER ATTOR NEY July 14, 1964 w, E. SOONG ETAL 3,140,567

LENS CENTERING AND BEVELING MACHINE Filed Jan. 16, 1963 4 Sheets-Sheet 4 0) U) E n:

a 2 \IO 1 k i I I O 6 I 1 8 I i n: m 1 I r' I I0 I g I l l I N 2 l w 9 I I m I L- 1 INVENTORS WILLIAM E. SOONG ROBERT E. MILLER JAMES DES JARDINS LAWRENCE HSHARPER ATTORNEYS United States Patent LENS CENTEG AND BEVELING MACHINE William E. Soong, Chicago, Robert E. Miller, Lombard,

and James Des Jardins, Chicago, EL, and Lawrence H.

Sharper, Philadelphia, Pa, assignors, by direct and mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Jan. 16, 1963, Ser. No. 251,992 7 Claims. (Cl. 51108) This invention relates to the manufacture of lenses. It provides a machine which greatly expedites the centering and grinding of lenses.

Conventional methods of centering and grinding lenses generally involve manual operations which require the presence of an attendant and contribute materially to the cost of the lens. The present invention provides a machine which operates continuously to receive a series of blank lenses one after another and functions automatically to center each lens and to thereafter pass it through a series of grinding stations. As will appear, this machine includes a number of spindle pairs each including a lower spindle fixed to an index table and an upper spindle biased into engagement with the lower spindle, means for raising the upper spindles at certain of the stations to permit entry, centering and discharge of the lens, and various control elements for effecting these operations automatically.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

Referring to the drawings:

FIG. 1 is a top view of the automatic lens centering and beveling machine,

FIG. 2 is a partial section taken on the line 22 of FIG. 1,

FIG. 3 illustrates a circuit which is utilized to raise and lower the upper spindles at the loading, centering and unloading stations,

FIG. 4 illustrates the means for centering the lens blank, this means being set into operation upon the raising of the spindles at the loading, centering and unloading stations,

FIG. 5 illustrates the means for controlling the feed and traversing movements of a lens grinding wheel,

FIG. 6 illustrates a contact device through which the connections of the circuit of FIG. 3 is controlled, and

FIG. 7 is a wiring diagram of the various connections of the system, only the positive lead of the voltage source being shown.

As indicated by FIGS. 1 and 2, the lens centering and beveling machine of the present invention includes a base 10 to which are fixed a six stop spindle positioning unit 11, an upright 12, a grinding wheel drive unit 13 and a rotary oscillating torque actuator 14. The upright 12 supports a photoelectric unit and a centering wheel mechanism 16. The drive unit 13 rotates a grinding wheel 17 and is mounted on a slide along which it is moved toward and from a lens blank 18, this movement being effected by the rotary oscillating torque actuator 14. The drive unit 13 and torque actuator 14 constitute a commercial- 1y available unit sold by Ex-Cell-O Corp., Greenville, Ohio and designated as Rotac HN34-U. The unit 11 drives an index table 19, bears the commercial designation Ferguson BT-121G-270 Intermittor, and is manufactured by Ferguson Machine Co. of St. Louis, M0. The unit 11 is provided with a Variable Dwell setting for predetermining the duration of time the index table 19 will remain at each of the various stations to be described hereinafter.

The Variable Dwell setting will only permit equal durations of time for each of the various stations and not predetermined durations of varying times.

Fixed to and rotatable with the index table 19 are six spindle pairs each including a lower spindle 20 which has a housing 21, a quick change spindle adapter 22 and a precision bearing 23. Also rotatable with and movable axially of the index table 19 are six upper spindles 24 which are supported by members 31 and 32. Each of these upper spindles includes a housing 33, a quick change adapter 34 and a spring 35 which functions to force the upper and lower spindles together during the grinding and indexing operations. Each of the upper spindles is alined with a corresponding lower spindle and together they are indexed by the drive unit from a loading station 36 (FIG. 1) successively to a lens centering station 37, a first grinding station 38, a second grinding station 39, a grinding and beveling station 40 and an unloading station 41.

Each of the upper spindles 24 is driven by a motor 25 to which it is coupled through a gear reducer 26 and a spindle drive gear 27 which is splined on the upper spindle shaft 28. A stationary center tube 29 supports the spindle drive motors 2.5, a vacuum adapter 30 and the spindle raising mechanism which includes a cast plate 42 and a hydraulic cylinder 43. As will appear, the cast plate 42 functions to raise the upper spindles 24 only at the loading station 36, the centering station 37 and the unloading station 41. This is accomplished by a flange which is located on the outer periphery of the cast plate and slides under the knobs 44 at the upper end of the spindle housing. A rod 45 functions to guide the cast plate 42 as it raises the spindles. The shafts of the various spindles are hollow and mounted near the upper end of the upper spindle shafts is a light source 46 which is energized through a slip ring 47. A vacuum pump connection 48 is pressed against the adapter 30 by a hydraulic cylinder 49 (Hydraulic Development Co. Model HB) which is of the one stroke type.

Located above each of the grinding stations 38, 39 and 40 is a hood 50 for evacuating the dust incident to the grinding of the lenses. A plurality of support stands 51, 52 and 53 are supported by the stationary center tube 29 as indicated by FIG. 1.

The hydraulic cylinder 43 for raising the upper spindles at loading station 36, centering station 37 and unloading station 41 has a 1 /2 inch bore, has a 1 inch stroke and is commercially designated as Miller Model H-65. It is controlled by the circuit of FIG. 3. This control circuit includes a solenoid operated 4-way valve 54 (Double-A Products, No. KF -C) which is spring centered to close all its ports and includes solenoids A and B.

Operation of this control circuit is initiated by an elec tric signal applied upon the indexing of the table 19 through an angle of 60 by the spindle positioning drive 11. This signal is transmitted from a terminal 87 (FIG. 6) through a brush 88, a slip ring 89, a brush 90, and a lead 57 and partially operates a relay 55 (FIG. 3) through which the solenoid A is actuated. Thereupon the valve 54 functions to admit operating fluid under pressure from a reservoir 56 to the cylinder 43 which raises the upper spindles at the loading, centering and unloading stations as previously indicated.

When the work at the loading, centering and unloading stations is completed, the table 19 is indexed to the next position by the spindle positioning unit 11. As the table starts its movement, a signal is applied to the partially operated relay 55 through lead 87 (FIG. 6), brush 88, slip ring 89, conductive segment 91, brush 92 and lead 58. This signal completes operation of the relay 55 thereby deenergizing solenoid A of the valve 54, energizing solenoid B, and returning the three upper spindles to their lower position. It is to be understood that the circuit contactor of FIG. 6 rotates with the index table 19 and that its brushes 9%) and 92 are so disposed that solenoids A and B (FIG. 3) are deenergized and all parts of the valve 54 are closed while the table is indexed and while the machine is idle. This prevents any undesired axial movement of the spindles.

FIG. 4 illustrates the lens blank centering control system. Operation of this system is initiated by a signal applied through a lead 59 when the spindles at stations 36, 37 and 41 are raised to their upper positions. This signal functions through a relay 60 to energize the B solenoid of a 4-way valve 61 which is spring centered to close all ports. Energization of the B solenoid allows operating fluid under pressure to flow from a reservoir 62 into the hydraulic cylinder 63 of the centering wheel operating mechanism 16 (FIG. 2). Thereupon a nylon centering wheel 64 is advanced toward the lens blank 18 which is held to the upper rotating spindle 24 by evacuating the spindle through the vacuum pump connection 48 (FIG. 2). The flow of the operating fluid is controlled by a needle valve flow regulator 65 at the exhaust port of the cylinder 63.

Immediately before the wheel 64 begins to bear against the lens 18, the final approach limit switch 66 is actuated to operate a solenoid operated 3-way valve 67 which is spring centered. Upon operation of the valve 67, the advance of the wheel 64 is slowed down under the control of the needle valve 68 and the wheel centers the lens until the beam from the light source apertures 69 passes through the lens 18 to the photocell 15 without bending.

At this point, the current through the photocell produces at the output of an amplifier 70 a voltage whereby the relay 60 is operated to (1) deenergize the B solenoid of the valve 61, (2) deenergize the solenoid of the valve 67, and (3) terminate advancement of the wheel 64. At the same time, the A solenoid of the valve 61 is energized and the wheel is moved back to its original standby position, this backward movement being relatively rapid due to the fact that the valves 65 and 68 are bypassed by a check valve 71 which permits a free flow of the operating fluid in the reverse direction.

In the standby position of the centering wheel mechanism 16, a rod 72 (FIG. 4) operates an adjustable limit switch 73 which deenergizes the relay 60 which in turn deenergizes the A solenoid of the valve 61. This permits the valve 61 to close so that all flow of operating fluid to the cylinder 63 is interrupted. The centered lens is thereupon indexed to the first grinding station 38 (FIG. 1).

Grinding of the lens is etfected with the lens clamped between an upper and lower spindle by the spring 35 (FIG. 2). The grinding wheel 17 is fed against the lens 18 by the hydraulic oscillating torque actuator 14 (Rotac HN IV-34) and is traversed across the edge of the lens by the drive unit.

Operation of the lens grinding feed and traversing system of FIG. is initiated by an electric signal applied to the lead 74 when the upper spindles at stations 36, 37 and 41 (FIG. 1) are raised to their working positions. This signal actuates a rotary actuator circuit relay 75, and through the relay 75, a hydraulic cylinder circuit relay 76. This actuates the A solenoids of (1) a solenoid operated, spring returned, 4-way valve 77 (Double A Products No. QJP 2-155-C) and (2) a solenoid operated spring centered 4-way valve 78 (Double A Products No. QFP 2-155-C).

Energization of the A solenoid of valve 77 admits operating fluid under pressure from the reservoir 79 to the rotary oscillating actuator 14 which advances the grinding wheel against the edge of the lens. Flow of the operating fluid is controlled by a needle valve flow regulator 80 at the actuator exhaust port. When grinding is completed, a micrometer-adjusted limit switch 81 is actuated to deenergize the relay 75 and stop the electric motor 25 (FIG. 2) and the spindle to the adapter of which the ground lens is attached. Deenergization of the relay 75 interrupts current in the A solenoid of the valve 77 which is spring returned .to reverse the flow of operating fluid to the rotary oscillating actuator and retract the grinding wheel to its original position. Fast return of the wheel results from the fact that the needle valve is shunted by a check valve 82.

Eenergization of the A solenoid of the valve 78 permits flow of the operating fluid to the drive unit 13 by which the grinding wheel is driven across the edge of the lens. At the end of the cylinder stroke, a limit switch 83 operates through the relaly 76 to deenergize the A solenoid and energize the B solenoid of the valve 78 for returning the grinding wheel to its original position. At the end of its return, a limit switch 86 operates through the relay 76 to deenergize the B solenoid and energize the A solenoid of the switch 78 thus initiating a repetition of the traversing cycle. When grinding is completed and the limit switch 81 has been actuated as indicated above to operate the relay 75, the solenoids of the valve 78 are deenergized and this valve is spring operated to close all its ports. During operation of the system, the traversing rate is controlled by the flow regulators 84 and 85.

As indicated by the wiring diagram of FIG. 7, operation of the system is initiated by closure of a main switch 93. This energizes the six stop drive unit 11 which indexes the table 19 to bring a set of upper and lower spindles to the lens centering stations. At this point a signal applied from the rotary contactor (FIG. 6) through the lead 57 functions as described in connection with FIG. 3 to raise the upper spindles at the loading, centering and unloading stations to their top positions. At this point, a connection is made through the cast plate 42 to the input lead 59 of the centering control circuit of FIG. 4 and the input lead 74 of the grinding feed and traversing control circuit 5. Thereupon these two circuits are operated as indicated in connection with FIGS. 4 and 5, the cast plate being maintained in its upper position while work is completed at the loading, centering and unloading stations. Upon the completion of this work, the table 19 is indexed to the next position by the six stop drive unit 11, a signal being applied through the lead 58 at the start of the indexing and the spindles being returned to their lower position by this signal.

We claim:

1. A lens grinding mechanism including a support,

an index table rotatable on said support,

a plurality of spindle pairs spaced apart along a circumference of said table at loading, lens centering, lens grinding and unloading stations, each of said pairs including a lower spindle fixed to said table and an upper spindle rotatable with and movable axially of said table,

a multispeed device for rotating said table with a stop of equal predetermined durations at each of said stations,

means operable upon the rotation of said table to raise said upper spindles at said loading, centering and unloading stations at the beginning of said stop and to lower said upper spindles at said loading, centering and unloading stations at the end of said stop,

a lens centering wheel,

a lens grinding wheel, and

means operable upon the raising of said upper spindles at said loading, centering and unloading stations to initiate operation of said wheels and operable upon the lowering of said upper spindles at said loading, centering and unloading stations to terminate the operation of said Wheels.

2. A lens grinding mechanism according to claim 1 wherein said upper spindles are hollow and connected to means for producing therein a vacuum for holding a lens against the lower end thereof during the operation of said centering wheel.

3. A lens grinding mechanism including a support,

an index table rotatable on said support,

a plurality of spindle pairs spaced apart along a circumference of said table at loading, lens centering, lens grinding and unloading stations, each of said pairs including a lower spindle fixed to said table and an upper spindle rotatable with and movable axially of said table,

a multispeed device for rotating said table with a stop of equal predetermined durations at each of said stations,

means operable upon the rotation of said table to raise said upper spindles at said loading, centering and unloading stations at the beginning of said stop and to lower said upper spindles at said loading, centering and unloading stations at the end of said stop,

a lens centering wheel,

a lens grinding wheel, and

centering wheel control means,

grinding wheel control means, and

means operable upon the raising of said upper spindles at said loading, centering and unloading stations to energize said centering wheel control means and grinding wheel control means and operable upon the lowering of said upper spindles at said loading, centering and unloading stations to cleenergize said t3 centering wheel control means and grinding wheel control means.

4. A lens grinding mechanism according to claim 1 including means for rotating said upper spindles, and means operable to energize said spindle rotating means upon the raising of said upper spindles at said loading, centering and unloading stations and to deenergize said spindle rotating means upon the lowering of said upper spindles at said loading, center and unloading stations.

5. A mechanism according to claim 3 wherein said grinding wheel control means includes means for simultaneously advancing said grinding wheel toward and transversely of the edge of a lens held between the upper and lower spindles at said grinding station.

6. A lens grinding mechanism according to claim 2 wherein said lower spindles are hollow, said upper spindles contain a light source, and a photoelectric cell having a restricted aperture is alined with said spindles whereby said photoelectric cell conducts when a lens held by said upper spindle at said centering station is centered.

7. A lens grinding mechanism according to claim 6 including means operable by the output of said photoelectric cell to retract and deenergize said centering wheel.

References Cited in the file of this patent UNITED STATES PATENTS 1,900,112 Hoern Mar. 7, 1933 

1. A LENS GRINDING MECHANISM INCLUDING A SUPPORT, AN INDEX TABLE ROTATABLE ON SAID SUPPORT, A PLURALITY OF SPINDLE PAIRS SPACED APART ALONG A CIRCUMFERENCE OF SAID TABLE AT LOADING, LENS CENTERING, LENS GRINDING AND UNLOADING STATIONS, EACH OF SAID PAIRS INCLUDING A LOWER SPINDLE FIXED TO SAID TABLE AND AN UPPER SPINDLE ROTATABLE WITH AND MOVABLE AXIALLY OF SAID TABLE, A MULTISPEED DEVICE FOR ROTATING SAID TABLE WITH A STOP OF EQUAL PREDETERMINED DURATIONS AT EACH OF SAID STATIONS, MEANS OPERABLE UPON THE ROTATION OF SAID TABLE TO RAISE SAID UPPER SPINDLES AT SAID LOADING, CENTERING AND UNLOADING STATIONS AT THE BEGINNING OF SAID STOP AND TO LOWER SAID UPPER SPINDLES AT SAID LOADING, CENTERING AND UNLOADING STATIONS AT THE END OF SAID STOP, A LENS CENTERING WHEEL, 